title: Plasticity of recurrent l2/3 inhibition and gamma oscillations by whisker experience.
abstract: Local recurrent networks in neocortex are critical nodes for sensory processing, but their regulation by experience is much less understood than for long-distance (translaminar or cross-columnar) projections. We studied local L2/3 recurrent networks in rat somatosensory cortex during deprivation-induced whisker map plasticity, by expressing channelrhodopsin-2 (ChR2) in L2/3 pyramidal cells and measuring light-evoked synaptic currents in ex vivo S1 slices. In columns with intact whiskers, brief light impulses evoked recurrent excitation and supralinear inhibition. Deprived columns showed modestly reduced excitation and profoundly reduced inhibition, providing a circuit locus for disinhibition of whisker-evoked responses observed in L2/3 in vivo. Slower light ramps elicited sustained gamma frequency oscillations, which were nearly abolished in deprived columns. Reduction in gamma power was also observed in spontaneous LFP oscillations in L2/3 of deprived columns in vivo. Thus, L2/3 recurrent networks are a powerful site for homeostatic modulation of excitation-inhibition balance and regulation of gamma oscillations.
authors.affiliation: Department of Molecular and Cellular Biology, University of California Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA 94720, USA.
authors.forename: Yu R
authors.initials: YR
authors.lastname: Shao
authors.forename: Brian R
authors.initials: BR
authors.lastname: Isett
authors.forename: Toshio
authors.initials: T
authors.lastname: Miyashita
authors.forename: Jason
authors.initials: J
authors.lastname: Chung
authors.forename: Olivia
authors.initials: O
authors.lastname: Pourzia
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Gasperini
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Feldman
mesh_terms: D000818:Animals; D001931:Brain Mapping; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D012683:Sensory Deprivation / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology*; D014738:Vibrissae / Q000502:physiology*